Performance Improvement of Enhanced-Mode β-Ga2O3 MOSFETs by Partial Gate Recess Structure

Abstract

In this study, β-Ga₂O₃ films were grown on the c-plane sapphire substrate by metal–organic chemical vapor deposition. Gate-recessed heteroepitaxial β-Ga₂O₃ metal oxide semiconductor field effect transistors (MOSFETs) were fabricated to achieve enhanced mode operation. It was found that the conductivity of Ga₂O₃ films can be further improved by in situ doping and a partial gate recess. Output current increased from 4.21 to 5.76 mA/mm, R_on.sp decreased from 392 mΩ.cm² to 238 mΩ.cm²,and μ_FE increased from 15 cm²/(V s) to 19.9 cm²/(V s) for MOSFETs with partial gate recesses of 7 and 5 μm, respectively. Device threshold voltages are positive, possessing low R_on and impressive I_D on/off ratios. Breakdown voltage was increased using a gate field plate. In summary, device performance was improved using shorter gate recesses for enhanced mode β-Ga₂O₃ MOSFETs.